Electronic devices, such as paging receivers, alert the user when a message has been received. Such a device generally incorporates circuitry for monitoring operational parameters and alerting the user by visual indications or audible tones in a coded format when the status of one of the operational parameters exceeds a threshold. The user may be alerted, for example, when the battery drops below a specified voltage or when the pager is beyond the range of the base station. In one conventional paging receiver, when the status of one of the operational parameters exceeds a threshold, the user is alerted by an audible tone. The user of the paging receiver must, however, be familiar with the meaning of the tone before the tone can be interpreted. This problem is magnified when several different tones or combinations of different tones are used to indicate changes in more than one of the operational parameters. In this case, the user is expected to be able to associate a plurality of different tones with their meanings before he can respond to the status indicator. In another conventional paging receiver, a visible symbol or message is displayed on a presentation device, e.g., a liquid crystal display, to alert the user when the status of one of the operational parameters exceeds a threshold. The presentation of the visible status indicator may provide a problem for the user in that the user may not notice the status indicator until one of the operational parameters has critically exceeded a threshold. For example, if the user does not realize that the battery voltage has fallen below a specified level, the battery voltage may drop low enough that the memory of the paging receiver is lost.
In some automobiles, a pre-recorded voice message alerts the user when the status of one of the operational parameters has exceeded a threshold. When the pre-recorded voice message is presented, the user is immediately aware of the status of the corresponding operational parameter. However, the presentation of the pre-recorded voice message may be distracting or dangerous to the user in some situations. For example, the presentation of the voice message could jeopardize a policeman who is on patrol in a sensitive area.